Dick Johnson methodology for measuring glider performance

I was fortunate to be able to fly with Dick for his tests on my DG-1000. In the 2 seat glider, I flew and he recorded data.

The altimeter was calibrated against his known standard. The vibrator mentioned earlier was hooked to the altimeter mounting bolts to minimize friction effects. The trailing calibrated airspeed "bomb" was dropped out the vent window to about 25 ft below the glider to be in undisturbed air. These readings were later used to adjust the speeds we were holding on the AS indicator in the glider.

We would tow to 10,000 - 12,000 ft early in the morning in stable air. We then flew at various airspeeds from min sink to high cruise and timed 500 feet changes. Speeds were varied 2.5 kts at the lower speeds, and then every 5 kts at the higher speeds.

The tests were a tremendous learning experience. As we descended and started to encounter any thermals/turbulence, Dick would call of the measurements and we would then take another tow if the high conditions were still favorable. As we got down to about 2500 ft he said there are bumps (actually just wiggles and not workable thermals) so that is it for this flight. Not wanting to waste time, I pulled the spoilers and headed for the airport. He politely asked if he could fly and I said great, maybe I could learn something. He closed the spoilers and tried to work every wiggle while explaining that spoilers burn energy and should be avoided at all costs. Guess I quickly learned to never quit trying.